1. Field of the Invention
This invention relates to a tool for cutting, drilling, grinding, or polishing metallic or non-metallic materials. More specifically, this invention relates to a rotary tool which is suitable for cutting, drilling, grinding, or polishing metals such as iron, aluminum, and copper, or alloys of such metals, or non-metallic materials such as stone, monocrystalline or polycrystalline silicons, and ceramics.
2. Description of the Related Art
Plastics which are reinforced with inorganic long fibers are well known as "FRP". For example, in "Kogyo Zairyo (Industrial Material)", Vol. 37, No. 1, (published in 1989 by Nikkan Kogyo Shinbunsha) there is disclosed a FRP consisting of an alumina fiber reinforced epoxy resin. Such FRPs have been utilized in the field of structural members.
Examples of well-known conventional rotary tools include the carborundum grindstone and the alumina grindstone. The carborundum grindstone, for example, consists of a porous material that is manufactured by binding carborundum abrasive grains together by means of a binder. Because of its porous structure, however, it cannot contain a sufficient amount of abrasive grains, resulting in a rather poor working efficiency. In addition, its pores will become clogged with chips, so that it is subject to early deterioration in cutting quality.
Japanese Patent Examined Publication No. 54-4800 and Japanese Patent Unexamined Publication No. 59-97845 disclose a buffing material and a grindstone, which consist of porous materials made of glass fibers. However, glass fibers exhibit a low degree of hardness, so that their field of application is limited. Moreover, they are all porous, which means they are rather poor in working efficiency and subject to clogging.
Japanese Patent Application No. 63-47374 discloses a lapping material containing inorganic fibers. This lapping material, however, cannot be applied to a rotary tool; that is for a tool which is to be held at a certain angle with respect to the surface to be lapped.